The present invention relates to novel substituted quinoline-3-carboxamide derivatives, to methods for their preparation, to compositions containing them, and to methods and use for clinical treatment of disease resulting from autoimmunity, such as multiple sclerosis, insulin-dependent diabetes mellitus, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease and psoriasis and, furthermore, diseases where pathologic inflammation plays a major role, such as asthma, atherosclerosis, stroke and Alzheimer""s disease. More particularly, the present invention relates to novel quinoline derivatives suitable for the treatment of, for example, multiple sclerosis and its manifestations.
Autoimmune diseases, e.g. multiple sclerosis (MS), insulin-dependent diabetes mellitus (IDDM), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and psoriasis represent assaults by the body""s immune system which may be systemic in nature, or else directed at individual organs in the body. They appear to be diseases in which the immune system makes mistakes and, instead of mediating protective functions, becomes the aggressor (1).
MS is the most common acquired neurologic disease of young adults in Western Europe and North America. It accounts for more disability and financial loss, both in lost income and in medical care, than any other neurologic disease of this age group. There are approximately 250.000 cases of MS in the United States.
Although the cause of MS is unknown, advances in brain imaging, immunology, and molecular biology have increased researchers"" understanding of this disease. Several therapies are currently being used to treat MS, but no single treatment has demonstrated dramatic treatment efficacy. Current treatment of MS falls into three categories: treatment of acute exacerbations, modulation of progressive disease, and therapy for specific symptoms.
MS affects the central nervous system and involves a demyelination process, i.e., the myelin sheaths are lost whereas the axons are preserved. Myelin provides the isolating material that enables rapid nerve impulse conduction. Evidently, in demyelination, this property is lost. Although the pathogenic mechanisms responsible for MS are not understood, several lines of evidence indicate that demyelination has an immunopathologic basis. The pathologic lesions, the plaques, are characterized by infiltration of immunologically active cells such as macrophages and activated T cells (2).
In U.S. Pat. No. 4,547,511 and in U.S. Pat. No. 4,738,971 and in EP 59,698 some derivatives of N-aryl-1,2-dihydro-4-substituted-1-alkyl-2-oxo-quinoline-3-carboxamide are claimed as enhancers of cell-mediated immunity. The compound 
known as roquinimex (Merck Index 12th Ed., No. 8418; Linomide(copyright), LS2616, N-phenyl-N-methyl-1,2-dihydro-4-hydroxy-1-methyl-2-oxo-quinoline-3-carboxamide) belongs to this series of compounds. Roquinimex has been reported to have multiple immunomodulatory activities not accompanied with general immunosuppression (3-12).
Furthermore, in U.S. Pat. No. 5,580,882 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of conditions associated with MS. The particular preferred compound is roquinimex. In U.S. Pat. No. 5,594,005 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of type I diabetes. The particular preferred compound is roquinimex.
In WO 95/24195 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of inflammatory bowel disease. Particularly preferred compounds are roquinimex or a salt thereof. In WO95/24196 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of psoriasis. Particularly preferred compounds are roquinimex or a salt thereof.
In clinical trials comparing roquinimex to placebo, roquinimex was reported to hold promise in the treatment of conditions associated with MS (13,14). There are, however, some serious drawbacks connected to roquinimex. For example, it has been found to be teratogenic in the rat, and to induce dose-limiting side effects in man, e.g. a flu-like syndrome, which prevents from using the full clinical potential of the compound.
Further, in WO 92/18483 quinoline derivatives substituted in the 6-position with a RAS(O)n-group (RA=lower alkyl or aryl; n=0-2) are claimed, which posses an immunomodulating, anti-inflammatory and anti-cancer effect.
The substitution, i.e., type and pattern, of the above, specifically mentioned, compounds in the prior art places them outside the scope of the present invention.
A primary objective of the present invention is to provide structurally novel quinoline compounds which by virtue of their pharmacological profile, with high potency in experimental models and low level of side-effects, are considered to be of value in the treatment of disease resulting from autoimmunity and pathologic inflammation. Examples of such disease are multiple sclerosis, insulin-dependent diabetes mellitus, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease and psoriasis and other diseases where inflammation plays a major role, such as asthma, atherosclerosis, stroke and Alzheimer""s disease. More particularly, the present invention relates to novel quinoline derivatives suitable for the treatment of, for example, multiple sclerosis and its manifestations.
The term xe2x80x9ctreatmentxe2x80x9d as used herein includes prophylaxis as well as relieving the symptoms of disease.
It has now surprisingly been found that the novel compounds of general formula (I) 
wherein
R is selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl and allyl;
Rxe2x80x2 is selected from methyl, methoxy, fluoro, chloro, bromo, trifluoromethyl, and OCHxFY,
wherein x=0-2,
y=1-3 with the proviso that
x+y=3;
Rxe2x80x3 is selected from hydrogen, fluoro and chloro, with the proviso that Rxe2x80x3 is selected from fluoro and chloro only when Rxe2x80x2 is selected from fluoro and chloro;
R4 is selected from hydrogen and pharmaceutically acceptable inorganic cations, such as sodium, potassium and calcium, and organic cations such as monoethanolamine, diethanolamine, dimethylaminoethanol, morpholine and the like;
R5 is selected from ethyl, n-propyl, iso-propyl, methoxy, ethoxy, chloro, bromo, trifluoromethyl, and OCHxFy, and OCH2CHxFy 
wherein x=0-2,
y=1-3 with the proviso that
x+y=3;
R6 is hydrogen; or
R5 and R6 taken together are methylenedioxy;
are unexpectedly effective and specific in the treatment of individuals suffering from autoimmune and inflammatory diseases.
The compounds of general formula (I) may exist in different tautomeric forms and all such forms where such forms exist are included herein.
In a preferred embodiment of the invention R4 is selected from hydrogen or sodium,
R5 is selected from ethyl, methoxy, chloro and trifluoromethyl,
R5 and R6 taken together are methylenedioxy,
Rxe2x80x2 is selected from methyl, methoxy, fluoro, chloro and trifluoromethyl when Rxe2x80x3 is hydrogen and
Rxe2x80x3 is selected from metal- and para-fluoro provided that Rxe2x80x2 is ortho-fluoro.
Among the most preferred compounds of general formula (I) according to the present invention are:
N-ethyl-N-(3-fluoro-phenyl)-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide,
N-ethyl-N-(4-methoxy-phenyl)-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(2,4-difluoro-phenyl)-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(2,5-difluoro-phenyl)-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide,
N-ethyl-N-(3-methoxy-phenyl)-1,2-dihydro-4-hydroxy-5-ethyl-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(2-fluoro-phenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(2,4-difluoro-phenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(2,5-difluoro-phenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(4-chloro-phenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(4-trifluoromethyl-phenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(2,4-difluoro-phenyl)-1,2-dihydro-4-hydroxy-5,6-methylenedioxy-1-methyl-2-oxo-quinoline-3-carboxamide,
N-methyl-N-(4-methoxy-phenyl)-1,2-dihydro-4-hydroxy-5-trifluoromethyl-1-methyl-2-oxo-quinoline-3-carboxamide.
Several spontaneously occurring autoimmune diseases in man have experimental models that are spontaneously occurring in certain strains of laboratory animals or can be induced in laboratory animals by immunization with specific antigen(s) from the target organ.
Experimental autoimmune encephalomyelitis (EAE) as a model for autoimmune inflammatory diseases of the central nervous system (CNS) has been the most widely used model for the human disease multiple sclerosis.
Autoimmunity to type II collagen can experimentally be induced in certain strains of mice or rats and may lead to the development of polyarthritis. The collagen induced arthritis has several features in common with the human disorder rheumatoid arthritis.
The hallmark of asthma in humans is an increased reactivity of the airways to a range of chemical and physical stimuli. It is now widely accepted that products released from inflammatory cells, e.g. activated eosinophils, comprise epithelial integrity and promote bronchial hyperresponsiveness. The murine model of ovalbumin (OA)-induced lung inflammation is dominated by the temporally regulated influx of lymphocytes and eosinophils into the bronchial lumen.
Roquinimex has been found to induce the Beagle Pain Syndrome (BPS)(15,16) in different breeds of beagle dogs. The disease is reflected by clinical and laboratory manifestations justifying BPS as a model for the flu-like syndrome induced by roquinimex in man.
The compounds of general formula (I) were assayed for inhibition of acute experimental autoimmune encephalomyelitis (aEAE) in mice. Roquinimex was used as treatment control and showed a more than 50% inhibition at xe2x89xa75 mg/kg. Surprising and unexpected results were obtained when introducing proper substitution in the 5-position of the quinoline ring. In comparison with roquinimex, the potency of the 5-chloro substituted compound was increased a 100-fold. Substitution in the 6-, 7-, and 8-position resulted in less active compounds. The effect of the 5-substitution could largely be understood on physicochemical grounds. In general EAE activity as seen by the EAE inhibition was in the following descending order according to the position of the substitution: 5 greater than 6 greater than  greater than 7=8. The comparison of the effects of 5- and 6-substitution showed that there is a statistically significant difference on every normal level (p less than 0.001) between the two, the effect of the 5-substitution being superior. Furthermore, proper aromatic substitution in the quinoline moiety and the 3-carboxamide moiety of the compounds of general formula (I) significantly reduced or even abolished the side effects, i.e. the teratogenic effect and the BPS, of roquinimex. Thus, physicochemical properties of the 5-substituent in the quinoline moiety and the ortho-, meta- and/or, in particular, the para-substituent in the 3-carboxamide moiety are of major importance for an improved risk/benefit ratio in comparison with roquinimex. Replacement of the methyl group on the carboxamide nitrogen with a higher alkyl group reduced the side effects even further. Hence, the compounds of formula (I) have surprisingly been found to be both chemically and pharmacologically different from those drugs hitherto suggested for the treatment of MS and its manifestations.
All embodiments of the invention as disclosed in the claims are herewith included in the specification.
The following examples are intended to illustrate the invention without restricting the scope thereof.
The compounds of general formula (I) may be prepared by methods known in the literature and the following methods:
Method A: 
The compounds of general formula (I) may be prepared by known methods and, for example, as shown above, by reaction of an ester derivative of the quinoline carboxylic acid with an aniline in a suitable solvent such as toluene, xylene and the like. General methods for preparation of the quinoline carboxylic acid ester derivatives of formula (II) are described below. N-alkylated anilines of formula (III) are commercially available or known from literature, e.g. in Johnstone et al, J. Chem. Soc. 1969, 2223-2224. Compounds falling within the scope of formula (III) may be prepared by methods, which are generally analogous to those of said literature.
Method B: 
The compounds of formula (I) may also be prepared by reaction of a quinoline carboxylic acid of formula (IV) with an aniline of formula (III). Various coupling reagents known in the art may be used, e.g., carbodiimides known from literature in U.S. Pat. No. 4,547,511. One suitable coupling method utilises thionyl chloride in the presence of triethylamine and a suitable solvent such as dichloromethane. This method may be used in instances when direct coupling between ester and aniline does not work, e.g., when the aniline contains electron withdrawing substituents. The quinoline carboxylic acids of formula (IV) may be obtained from the corresponding esters of formula (II) by acidic hydrolysis as described below.